在本章中，将学习如何使用Web服务上载和下载文件。
上传文件
对于上载文件，要将MultipartFile用作请求参数，此API应使用多部分表单数据值。 观察下面给出的代码 -
@RequestMapping(value = "/upload", method = RequestMethod.POST, consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
public String fileUpload(@RequestParam("file") MultipartFile file) {
return null;
}
Java
下面给出了相同的完整代码 -
package com.felix.demo.controller;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
@RestController
public class FileUploadController {
@RequestMapping(value = "/upload", method = RequestMethod.POST,
consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
public String fileUpload(@RequestParam("file") MultipartFile file) throws IOException {
File convertFile = new File("/var/tmp/"+file.getOriginalFilename());
convertFile.createNewFile();
FileOutputStream fout = new FileOutputStream(convertFile);
fout.write(file.getBytes());
fout.close();
return "File is upload successfully";
}
}
文件下载
对于文件下载，应该使用InputStreamResource下载文件。需要在Response中设置HttpHeader Content-Disposition，并且需要指定应用程序的响应Media Type。
注 - 在以下示例中，文件应在运行应用程序的指定路径上可用。
@RequestMapping(value = "/download", method = RequestMethod.GET)
public ResponseEntity<Object> downloadFile() throws IOException {
String filename = "/var/tmp/mysql.png";
File file = new File(filename);
InputStreamResource resource = new InputStreamResource(new FileInputStream(file));
HttpHeaders headers = new HttpHeaders();
headers.add("Content-Disposition", String.format("attachment; filename=\\"%s\\"", file.getName()));
headers.add("Cache-Control", "no-cache, no-store, must-revalidate");
headers.add("Pragma", "no-cache");
headers.add("Expires", "0");
ResponseEntity<Object>
responseEntity = ResponseEntity.ok().headers(headers).contentLength(file.length()).contentType(
MediaType.parseMediaType("application/txt")).body(resource);
return responseEntity;
}
下面给出了相同的完整代码 -
package com.felix.demo.controller;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import org.springframework.core.io.InputStreamResource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class FileDownloadController {
@RequestMapping(value = "/download", method = RequestMethod.GET)
public ResponseEntity<Object> downloadFile() throws IOException {
String filename = "/var/tmp/mysql.png";
File file = new File(filename);
InputStreamResource resource = new InputStreamResource(new FileInputStream(file));
HttpHeaders headers = new HttpHeaders();
headers.add("Content-Disposition", String.format("attachment; filename=\\"%s\\"", file.getName()));
headers.add("Cache-Control", "no-cache, no-store, must-revalidate");
headers.add("Pragma", "no-cache");
headers.add("Expires", "0");
ResponseEntity<Object>
responseEntity = ResponseEntity.ok().headers(headers).contentLength(
file.length()).contentType(MediaType.parseMediaType("application/txt")).body(resource);
return responseEntity;
}
}
主要的Spring Boot应用程序如下 -
package com.felix.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
Maven构建文件 - pom.xml 的代码如下 -
<?xml version = "1.0" encoding = "UTF-8"?> <project xmlns = "http://maven.apache.org/POM/4.0.0" xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation = "http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.felix</groupId> <artifactId>demo</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>demo</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.8.RELEASE</version> <relativePath/> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
Gradle构建文件 - build.gradle 的代码如下 -
buildscript {
ext {
springBootVersion = '1.5.8.RELEASE'
}
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'
group = 'com.felix'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8
repositories {
mavenCentral()
}
dependencies {
compile('org.springframework.boot:spring-boot-starter-web')
testCompile('org.springframework.boot:spring-boot-starter-test')
}
现在创建一个可执行的JAR文件，并使用下面给出的Maven或Gradle命令运行Spring Boot应用程序：
对于Maven，请使用下面给出的命令 -
mvn clean install
在“BUILD SUCCESS”之后，在target目录下找到JAR文件。
对于Gradle，可以使用下面显示的命令 -
gradle clean build
在“BUILD SUCCESSFUL”之后，在build/libs 目录下找到JAR文件。
现在，使用以下命令运行JAR文件 -
java –jar <JARFILE>
这将在Tomcat端口8080上启动应用程序。
现在点击 POSTMAN 应用程序中的以下URL，可以看到如下所示的输出 -
文件上传 - http://localhost:8080/upload
文件下载 - http://localhost:8080/download